4-[(meth)acrylamidomethyl]-pyrazoles and -isoxazoles, their preparation and their use

ABSTRACT

Novel 4-[(meth)acrylamidomethyl]-pyrazoles and -isoxazoles of the general formula ##STR1## where R is hydrogen or methyl, R 1  is hydrogen, methyl or ethyl, R 2  and R 3  may be identical or different and are each alkyl of 1 to 6 carbon atoms or unsubstituted or substituted aryl of 6 to 20 carbon atoms, and X is oxygen or an NR 4  group where R 4  is hydrogen or a radical having the meanings of R 2  or R 3 , a process for their preparation, and the use of these compounds in particular for polymerization and the preparation of homopolymers and copolymers, are described.

This application is a division of application Ser. No. 360,987, filed onJune 2, 1989.

The present invention relates to novel4-[(meth)acrylamidomethyl]-pyrazoles and -isoxazoles.

The present invention furthermore relates to a process for thepreparation of these compounds and novel homolymers and copolymersprepared using these compounds.

Compounds which contain a heterocyclic group and an olefinicallyunsaturated radical capable of undergoing polymerization have long beenknown. Typical examples of these are vinylpyridine, N-vinylpyrrolidoneand N-vinylcarbazole. They can readily be converted into homopolymers orcopolymers which, although they have a wide range of applications, donot always meet all requirements in some fields of use, for example inthe area of photosensitive offset printing plates or surface coatings.

In the area of surface coatings, the compounds which are disclosed inEP-A-188 037 and in which a heterocyclic group is bonded to a(meth)acrylic acid radical have resulted in a certain amount ofprogress. Typical examples of the compounds described in EP-A-188 037are ##STR2##

In these known compounds, the heterocyclic group is bonded to the(meth)acryloyl radical via one or two ester. functions. The use of thehomopolymers and copolymers prepared therefrom in the area ofphotosensitive offset printing plates is not evident from EP-A-188 037.

Apart from this, these compounds have the disadvantage that the esterfunctions present therein are readily hydrolyzable. Hence, the compoundsdecompose in the presence of water, aqueous alkaline solutions, ammoniaor amines. They are therefore suitable only for applications in whichthere is no danger of decomposition and the associated loss of thetypical properties. Morever, many synthesis steps are required in thepreparation of these compounds in order to achieve bonding of theheterocyclic group to the (meth)acryloyl radical, further reducing theattractiveness of these compounds.

It is an object of the present invention to provide novel, stablecompounds which are simple to prepare and in which a heterocyclic groupis bonded to a radical containing an olefinic double bond which can besubjected to free radical polymerization, the said compounds not havingthe disadvantages of the prior art.

We have found, surprisingly, that this object is achieved by4-[(meth)acrylamidomethyl]-pyrazoles and -isoxazoles of the type definedand described below.

The present invention accordingly relates to4-[(meth)acrylamidomethyl]-pyrazoles and -isoxazoles of the generalformula (I) ##STR3## where R, R¹, R², R³ and X independently of oneanother have the following meanings: R is hydrogen or methyl, preferablyhydrogen, R¹ is hydrogen, methyl or ethyl, preferably hydrogen, R² andR³ may be identical or different and are each alkyl of 1 to 6 carbonatoms or aryl of 6 to 20 carbon atoms which is unsubstituted orsubstituted by, for example, alkyl, aryl or halogen, and X is oxygen oran NR⁴ group, where R⁴ is hydrogen or a radical having the meanings ofR² or R³.

Examples of the radicals R² and R³ in the general formula (I) aremethyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl,pent-1-, -2- or -3-yl and hex-1-, -2- or -3-yl, and furthermore phenyl,2-, 3- and 4-methylphenyl, 2,4-dimethylphenyl, 4-tert-butyl-, 4-chloro-and 4-bromophenyl, 4-phenylphen-1-yl (biphenylyl),4-(4'-phenylphen-1'-yl)-phen-1-yl (triphenylyl), 1- and 2-naphthyl,phenanthren-7-yl, anthracen-1-yl, fluoren-2-yl and perylen-3-yl. Ofthese radicals, methyl, ethyl, n-propyl and phenyl are preferredaccording to the invention, methyl and phenyl being very particularlypreferred.

Examples of R⁴ are the groups stated above for R² and R³. R⁴ ispreferably hydrogen, methyl, ethyl, n-propyl or phenyl, in particularhydrogen or phenyl.

Examples of preferred novel 4-[(meth)acrylamidomethyl]-pyrazoles and-isoxazoles of the general formula (I) are ##STR4##

Of these, the compounds I-6[3-phenyl-4-(acrylamidomethyl)-5-methylisoxazole], I-7[3-phenyl-4-(acrylamidomethyl)-5-methylpyrazole], I-9[1,3,5-triphenyl-4-(acrylamidomethyl)-pyrazole] and I-11[1,5-diphenyl-3-methyl-4-(acrylamidomethyl)-pyrazole] are veryparticularly preferred.

The novel 4-[(meth)acrylamidomethyl]-pyrazoles and -isoxazoles of thegeneral formula (I) can be prepared by conventional and known methods ofpreparative organic chemistry. However, it is advantageous to preparethe novel 4-[(meth)acrylamidomethyl]-pyrazoles and -isoxazoles of thegeneral formula (I) by a novel procedure, by condensation of a suitable1,3-diketone with (a) a hydrazine or with (b) a hydroxylamine.

This novel process starts from a 1,3-diketone of the general formula(II) ##STR5## where R² and R³ may be identical or different andindependently of one another are each alkyl of 1 to 6 carbon atoms orunsubstituted or substituted aryl of 6 to 20 carbon atoms. Examples ofthe radicals R² and R³ in the general formula (II) are the radicalsstated for R² and R³ in the general formula (I). Of these radicals,methyl, ethyl, n-propyl and phenyl are particularly preferred accordingto the invention, methyl and phenyl being very particularly preferred.

Examples of 1,3-diketones of the general formula (II) which are veryparticularly preferably used in the novel process are pentane-2,4-dione(II-1), benzoylacetore (II-2) and 1,3-diphenylpropane-1,3-dione (II-3).

In the novel procedure, the 1,3-diketones of the general formula (III)are dissolved or dispersed in a sufficient amount of a strong acid as areaction medium at from -5° to +10° C., in particular at about 0° C. Asuitable amount of acid is in general about from 2 to 20 times theweight of the 1,3-diketone of the general formula (II). Suitable strongacids include concentrated sulfuric acid, concentrated phosphoric acidand concentrated trifluoromethanesulfonic acid, of which thefirst-mentioned is particularly advantageous.

An equimolar amount of an N-methylol(meth)acrylamide of the generalformula (III) ##STR6## where R is hydrogen or methyl and, independentlyof this, R¹ is hydrogen, methyl or ethyl, is then added to this solutionor dispersion of the 1,3-diketone of the general formula (II). Accordingto the invention, N-methylol(meth)acrylamides of the general formula(III) where R¹ is hydrogen are preferred here. N-methylolacrylamide isvery particularly preferred. It is known that theN-methylol(meth)acrylamides of the general formula (III) can be preparedin a simple manner from formaldehyde and the corresponding(meth)acrylamide.

According to the invention, it is advantageous to add a conventional andknown thermal polymerization inhibitor to the resulting reactionmixture. Examples of suitable polymerization inhibitors aretrisnonylphenyl phosphite, 2,6-di-tert-butyl-p-cresol, hydroquinonemonomethyl ether and polymerized trimethyldihydroquinone, of whichhydroquinone monomethyl ether is particularly advantageous. Thepolymerization inhibitors are added to the reaction mixture in amountsof from 0.001 to 5% by weight, based on the N-methylol(meth)acrylamideof the general formula (III).

The resulting reaction mixture of the 1,3-diketone of the generalformula (II), the N-methylol(meth)acryalmide of the general formula(III), the strong acid and, if required, the polymerization inhibitor isthen stirred at from 15° to 40° C., preferably from 15° to 30° C., inparticular from 20° to 25° C., for from 1 to 48, preferably from 2 to40, in particular from 2.5 to 20, hours. During this time, thecondensation reaction takes place between the 1,3-diketone of thegeneral formula (II) and the N-methylol(meth)acrylamide of the generalformula (III) to give the relevant2-[(meth)acrylamidomethyl]-1,3-diketone of the general formula (IV).##STR7##

In the general formula (IV), R, R¹, R² and R³ have the meanings statedabove for these radicals in connection with the general formulae (II)and (III).

The reacted mixture is then poured onto a large excess of, preferablycrushed, ice, with the result that the relevant2-[(meth)acrylamidomethyl]-1,3-diketone of the general formula (IV) isprecipitated. The precipitate and any product still present in theaqueous phase are then extracted with an organic solvent, for exampletoluene, xylene or a halohydrocarbon, such as dichloromethane, thesolvent is evaporated off and the residue is then recrystallized from asuitable solvent or solvent mixture.

For the preparation of the novel 4-[(meth)acrylamidomethyl]-pyrazoles ofthe general formula (I), the 2-[(meth)acrylamidomethyl]-1,3-diketones ofthe general formula (IV) are condensed with a preferably equimolaramount of a hydrazine by the novel process.

Examples of suitable hydrazines to be used according to the inventionare hydrazinium salts, such as hydrazinium fluoride, chloride, bromide,bisulfate, dihydrogenphosphate and trifluoromethanesulfonate, of whichhydrazinium bisulfate is preferably used. Other examples of suitablehydrazines are hydrazine derivatives of the general formula (V)

    NH.sub.2 --NH--R.sup.4                                     (V)

where R⁴ is one of the radicals R² or R³ described above. Of thesehydrazine derivatives of the general formula (V), phenylhydrazine ispreferably used.

For the preparation of the novel 4-[(meth)acrylamidomethyl]-isoxazolesof the general formula (I), the 2-[(meth)acrylamidomethyl]-1,3-diketonesof the general formula (IV) are condensed with a preferably equimolaramount of hydroxylamine, preferably a hydroxylammonium salt, by thenovel process. Examples of hydroxylammonium salts which are preferablyused according to the invention are hydroxylammonium fluoride, chloride,bromide, bisulfate, dihydrogenphosphate and trifluoromethanesulfonate,of which hydroxylammonium chloride is particularly preferably used.

Regardless of whether the novel 4-[(meth)acrylamido:methyl]-pyrazoles ofthe general formula (I) or the novel4-[(meth)acrylamidomethyl]-isoxazoles of the general formula (I) areproduced from the 2-[(meth)acrylamido:aethyl]-1,3-diketones of thegeneral formula (IV) in the novel process, the relevant condensation ofthe 1,3-diketones of the general formula (IV) with the hydrazines or thehydroxylamines is carried out in an aqueous reaction medium. For thepurposes of the present invention, an aqueous reaction medium is waterwhich contains dissolved or dispersed organic and/or inorganicadditives.

Examples of suitable additives which are present in the aqueous reactionmedium include carboxylic acids, such as acetic acid, propionic acid orbutyric acid, of which acetic acid is preferred. Other examples ofsuitable additives of the type under discussion are carboxylic acidsalts, such as sodium acetate, potassium acetate, sodium propionate,potassium propionate, sodium butyrate and potassium butyrate, of whichsodium acetate is preferably used. Suitable aqueous reaction mediacontain water and the additives in a weight ratio of water to additivesof from 1:5 to 1:1.

Examples of aqueous reaction media preferably used according to theinvention are

water plus acetic acid in a weight ratio of from 1:5 to 1:1 or

water plus acetic acid plus sodium acetate in a weight ratio of from1:1:0.05 to 1:1:0.2.

The narrower choice of the aqueous reaction medium which is mostsuitable for the relevant condensation depends in particular on thesolubility and/or dispersibility of the reactants in this aqueousreaction medium and can be made on the basis of simple preliminaryexperiments.

Regardless of the particular aqueous reaction medium in which the novelprocess is carried out, the condensation reaction is effected either bya procedure in which one of the reactants in the aqueous reaction mediumis initially taken and the other reactant is metered in a little at atime or continuously, or by a procedure in which both reactants aredissolved and/or dispersed simultaneously in the relevant aqueousreaction medium. According to the invention, it is advantageous here toadd the two reactants simultaneously to the aqueous reaction medium andto carry out the condensation batchwise in a one-vessel process.

Regardless of the manner in which the novel process is carried out, thecondensation between the relevant reactants is effected at the boilingpoint of the aqueous reaction medium, ie. under reflux. The reactiontime after which the condensation reaction has come to an end is usuallyfrom 1 minute to 2 hours, in particular about from 2 minutes to 1 hour,preferably about from 3 to 30 minutes. The optimum reaction time for theparticular condensation depends on the reactivity of the reactants usedin each case and can be determined by preliminary experiments.

After the end of the condensation reaction, the resulting reactionmixture is allowed to cool to room temperature. During this procedure,the novel 4-[(meth)acrylamidomethyl]-pyrazoles or -isoxazoles of thegeneral formula (I) crystallize out, or they are precipitated bydiluting the reaction mixture with from two to ten times the amount,based on the reaction mixture, of water.

The products which have crystallized out or have been precipitated areisolated in a conventional and known manner, for example by filtrationor centrifuging, and are washed with a suitable organic liquid, e.g.diethyl ether, and/or recrystallized from a suitable solvent or solventmixture, e.g. methanol, ethanol, isopropanol or ethanol/isopropanol.

The 4-[(meth)acrylamidomethyl]-pyrazoles or -isoxazoles of the generalformula (I) obtained in the novel procedure are as a rule then alsodried. They can be characterized in a conventional and known manner.

The novel process can be carried out in any glass or metal apparatus ofthe type conventionally used in the field of preparative organicchemistry.

The novel 4-[(meth)acrylamidomethyl]-pyrazoles and -isoxazoles of thegeneral formula (I), in particular those prepared by the novel process,have particular, advantageous properties and therefore have manypotential applications. For example, they are useful intermediates fororganic syntheses. In particular, they can be used as polymerizablemonomers, in particular monomers which can be subjected to free radicalpolymerization, preferably photopolymerizable monomers. They aretherefore particularly useful for the preparation of novel,photopolymerizable sealing compounds, surface coatings, adhesives andsheet-like recording materials, to which they impart unexpectedlyadvantageous performance characteristics.

The novel 4-[(meth)acrylamidomethyl]-pyrazoles or -isoxazoles of thegeneral formula (I) are particularly advantageously used for thepreparation of homopolymers or copolymers, and, for the preparation ofcopolymers, the novel pyrazoles or isoxazoles of the general formula (I)can be copolymerized with one another and/or with other conventionalmonomers. Here, they display the advantageous properties even in thecopolymers with other conventional monomers, with the result that thesenovel copolymers are very suitable, for example, as binders inphotosensitive offset printing plates.

Another important advantage of the novel4-[(meth)acrylamidomethyl]-pyrazoles and -isoxazoles of the generalformula (I) is that they can be polymerized or copolymerized by thethermally or photochemically initiated free radical polymerizationmethods familiar from polymer chemistry. For example, they can be(co)polymerized by mass polymerization, i.e. in the absence of asolvent, or in solution, and the conventional and known free radicalinitiators, such as organic peroxides, azo compounds, stericallyhindered hydrocarbons (C-C initiators), redox initiators orphotoinitiators, can be used.

The novel 4-[(meth)acrylamidomethyl]-pyrazoles and -isoxazoles of thegeneral formula (I) can be particularly advantageously copolymerizedwith the conventional and known monomers from the group consisting ofthe

vinylaromatics, e.g. styrene, α-methylstyrene or p-methylstyrene;

nitriles, e.g. acrylonitrile or methacrylonitrile;

olefinically unsaturated carboxylic acids and their anhydrides, e.g.(meth)acrylic acid, (meth)acrylic anhydride or maleic anhydride;

esters of (meth)acrylic acid, e.g. ethyl (meth)acrylate, 2-hydroxyethyl(meth)acrylate or benzyl acrylate;

esters of fumaric or maleic acid, e.g. di-n-butyl or di-n-octyl fumarateor maleate;

(meth)acrylamides, e.g. N-hexyl(meth)acrylamide;

vinyl ethers, e.g. vinyl butyl ether;

vinyl esters, e.g. vinyl acetate or propionate;

allyl ethers, e.g. allyl butyl ether;

allyl esters, e.g. bisallyl itaconate; or

alkadienes, e.g. butadiene or isoprene,

this list by no means being exhaustive but merely giving typicalexamples which should be regarded as an indication of other suitable,conventional and known monomers.

Regardless of their intended use and/or of the method by which they arefurther processed, both the novel 4-[(meth)acrylamidomethyl]-pyrazolesand -isoxazoles of the general formula (I) and the novel (co)polymersprepared therefrom prove to be very stable to hydrolysis. There istherefore no danger of the bond between the heterocyclic group and the(meth)acryloyl radical capable of free radical polymerization or the(co)polymer being cleaved by undesirable side reactions, which wouldresult in a loss of the particularly advantageous properties typical ofthe novel substances.

EXAMPLES

For the synthesis of the novel 4-[(meth)acrylamidomethyl]-pyrazoles and-isoxazoles, two 2-[(meth)acrylamidomethyl]-1,3-diketones were firstprepared (Synthesis Examples I and II).

SYNTHESIS EXAMPLE I

Preparation and characterization of1-phenyl-2-(acrylamidomethyl)-butane-1,3-dione

1.0 g of hydroquinone monomethyl ether, 100 g of benzoylacetone and 64.8g of N-methylolacrylamide were introduced one after the other into 500ml of concentrated sulfuric acid at 0° C. The stirred reaction mixturewas left to react at 20° C. for 4 hours, after which it was poured onto2 kg of crushed ice. The 1-phenyl-2-(acrylamidomethyl)-butane-1,3-dioneprecipitated during this procedure was dissolved in dichloromethane andthe resulting solution was separated off from the aqueous phase. Thedichloromethane was then evaporated.

Recrystallization of the product from a mixture of 3 parts by volume ofcyclohexane and 1 part by volume of ethanol gave 105 g of1-phenyl-2-(acrylamidomethyl)-butane-1,3-dione, corresponding to a yieldof pure product of 70% by weight, based on the starting materials. Theproduct had a melting point of 125°-126° C.

Elemental analysis: C 68.7; H 6.0; O 19.7 ; N 5.7.

Theory: C 68.56H 6.16; O 19.57; N 5.71.

The ¹ H-NMR and IR spectroscopic measurements confirmed the presence ofthe desired compound.

SYNTHESIS EXAMPLE II

Preparation and characterization of1,3-diphenyl-2-(acrylamidomethyl-propane-1,3-dione

1,3-Diphenyl-2-(acrylamidomethyl)-propane-1,3-dione was prepared from143 g of 1,3-diphenylpropane-1,3-dione and 64.8 g ofN-methylolacrylamide similarly to the method described in SynthesisExample I.

Recrystallization of the product from methanol gave 127 g of1,3-diphenyl-2-(acrylamidomethyl)-propane-1,3-cione, corresponding to ayield of pure product of 65% by weight. The product had a melting pointof 146°-148° C.

Elemental analyis: C 74.1; H 5.6; O 15.8; N 4.5.

Theory: C 74.25; H 5.58; O 15.62; N 4.56.

The ¹ H-NMR and IR spectroscopic measurements confirmed the presence ofthe desired compound

EXAMPLE 1

3-Phenyl-4-acrylamidomethyl-5-methylisoxazole

A mixture of 34.6 g of the1-phenyl-2-(acrylamidomethyl)-butane-1,3-dione prepared according toSynthesis Example I, 9.84 g of hydroxylammonium chloride, 11.6 g ofsodium acetate, 180 ml of acetic acid and 180 ml of water was refluxedfor 5 minutes, cooled to room temperature and then diluted with 600 mlof water. The crystals precipitated in this procedure were filtered offunder suction and washed with diethyl ether. This gave 27.0 g of3-phenyl-4-acrylamidomethyl-5-methylisoxazole, corresponding to a yieldof 79% by weight. The product had a melting point of 149°-151° C.

Elemental analysis: C 59.4; H 5.9; O 13.1; N 11.6.

Theory: C 69.41; H 5.82; O 13.21; N 11.56.

The ¹ H-NMR and IR spectroscopic measurements confirmed the presence ofthe desired compound.

EXAMPLE 2

3-Phenyl-4-acrylamidomethyl-5-methylpyrazole

A mixture of 29.4 g of the1-phenyl-2-(acrylamidomethyl)-butane-1,3-dione prepared according toSynthesis Example I, 15.6 g of hydrazinium bisulfate, 19.7 g of sodiumacetate, 180 ml of acetic acid and 180 ml of water was refluxed for 5minutes, cooled to room temperature and then diluted with 600 ml ofwater. The crystals precipitated in this procedure were filtered offunder suction and washed with diethyl ether. This gave 23.1 g of3-phenyl-4-acrylamidomethyl-5-methylpyrazole, corresponcing to a yieldof 80% by weight. The product had a melting point of 191°-193° C.

Elemental analysis: C 69.4 H 6.3; N 17.2.

Theory: C 69.69; H 6.27; N 17.41.

The ¹ H-NMR and IR spectroscopic measurements confirmed the presence ofthe desired compound.

EXAMPLE 3

1,3,5-Triphenyl-4-acrylamidomethylpyrazole

A mixture of 67.4 g of the1,3-diphenyl-2-(acrylamidomethyl)-propane-1,3-dione prepared accordingto Synthesis Example II, 23.8 g of phenylhydrazine, 230 ml of aceticacid and 50 ml of water was heated at 90° C. for 6 minutes. The product(58.2 g) which crystallized out after cooling to room temperature wasrecrystallized from ethanol.

The recrystallized product had a melting point of 189°-191° C. The ¹H-NMR spectroscopic measurement confirmed the presence of1,3,5-triphenyl-4-acrylamidomethylpyrazole:

¹ H-NMR (dimethyl sulfoxide; 300 MHz): δ=4.20 (doublet, 2H, --CH₂ --)δ=5.60 (doublet, 1H, H--C═C) δ=6.15 (doublet, 1H, H--C═C) δ=6.30 (doubledoublet, 1H, H--C═C) δ=7.2-7.8 (multiplet, 15H, aromatic H) δ=8.60(triplet, 1H, NH)

EXAMPLE 4

1,5-Diphenyl-3-methyl-4-acrylamidomethylpyrazole

A mixture of 29.4 g of the1-phenyl-2-(acrylamidomethyl)-butane-1,3-dione prepared according toSynthesis Example I, 12.9 g of phenylhydrazine, 180 ml of acetic acidand 180 ml of water was refluxed for 5 minutes, cooled to roomtemperature and then diluted with 600 ml of water. The crystalsprecipitated in this procedure were filtered off under suction andwashed with diethyl ether. This gave 37.4 g of1,5-diphenyl-3-methyl-4-acrylamidomethylpyrazole having a melting pointof 157°-159° C. The ¹ H-NMR spectroscopic measurement confirmed thepresence of this product:

¹ H-NMR (dimethyl sulfoxide; 300 MHz): δ=2.5 (singlet, 3H, CH₃) δ=4.12(doublet, 2H, --CH₂ --) δ=5.60 (doublet, 1H, H--C═C) δ=6.12 (doublet,1H, H--C═C) δ=6.25 (double doublet, 1H, H--C═C) δ=7.10-7.45 (multiplet,10H, aromatic H) δ=8.30 (triplet, 1H, NH)

EXAMPLE 5

Preparation of a 3-phenyl-4-acrylamidomethyl-5-methylisoxazole copolymer

(i) A solution of 7.5 parts by weight of the3-phenyl-4-acrylamidomethyl-5-methylisoxazole prepared according toExample 1 in 40 parts by weight of acetone/N-methylpyrrolidone (volumeratio 3:1) and

(ii) a solution of 16.3 parts by weight of acrylonitrile, 71.1 parts byweight of ethyl acrylate, 4.3 parts by weight of methacrylic acid and0.1 part by weight of azobisisobutyronitrile in 3 parts by weight ofN-methylpyrrolidone were metered, in the course of 4 hours, into afournecked flask heated at 60° C. and equipped with a stirrer, aninternal thermometer, a dropping funnel and a reflux condenser. Thecombined solutions were then refluxed for a further hour, whilestirring.

Thereafter,

(iii) a solution of 2.3 parts by weight of methacrylic acid and 0.1 partby weight of azobisisobutyronitrile in 20 parts by weight of methanolwas metered into the reaction solution in the course of one hour, afterwhich the resulting mixture was refluxed for a further hour. Then,

(iv) a solution of 1.2 parts by weight of methacrylic acid and 0.1 partby weight of azobisisobutyronitrile in 20 parts by weight of methanoland

(v) a solution of 2 parts by weight of azobisisobutryonitrile in 80parts by weight of methanol were added.

The resulting reaction mixture was then refluxed until the remainingamount of acrylonitrile in the non-volatile part of the reaction mixturewas less than 0.1% by weight (determined by gas chromatography). Thecopolymer obtained was then isolated by evaporating off the solvent. Thecopolymer had a Fikentscher K value of 59 (measured in a 1% strength byweight solution of the copolymer in dimethylformamide) and an acidnumber of 58 mg of KOH/g.

EXAMPLE 6

Preparation of a 3-phenyl-4-acrylamidomethyl-5-methylpyrazole copolymer

Example 5 was repeated, except that, instead of the solutions (i) and(ii) used there, solutions of

(i) 15 parts by weight of the3-phenyl-4-acrylamidomethyl-5-methylpyrazole obtained according toExample 2 in 45 parts by weight of methanol and

(ii) 13.6 parts by weight of acrylonitrile, 63.6 parts by weight ofethyl acrylate, 4.3 parts by weight of methacrylic acid and 0.1 part byweight of azobisisobutyronitrile in 5 parts by weight of methanol wereused, and the combined solutions were refluxed for six hours instead ofone hour, after which the other solutions (iii) to (v) were added to thereaction mixture, as stated in Example 5.

The resulting copolymer had a Fikentscher K value of 38.4 and an acidnumber of 53 mg of KOH/g of copolymer.

EXAMPLE 7

Preparation of a further 3-phenyl-4-acrylamidomethyl-5methylpyrazolecopolymer

Example 5 was repeated, except that, instead of the solutions (i) to (v)used there, the following solutions were employed:

(i) 4.125 parts by weight of the3-phenyl-4-acrylamidomethyl-5-methylpyrazole obtained according toExample 2 in 18 parts by weight of methanol,

(ii) 13.6 parts by weight of acrylonitrile, 71.1 parts by weight ofethyl acrylate, 4.3 parts by weight of methacrylic acid and 0 1 part byweight of azobisisobutyronitrile in 2 parts by weight of methanol,

(iii) 2.3 parts by weight of methacrylic acid and 2.25 parts by weightof the 3-phenyl-4-acrylamidomethyl-5-methylpyrazole obtained accordingto Example 2 in 18 parts by weight of methanol,

(iv) 0.1 part by weight of azobisisobutyronitrile in 2 parts by weightof methanol and

(v) 1.2 parts by weight of methacrylic acid and 2.25 parts by weight ofthe 3-phenyl-4-acrylamidomethyl-5-methylpyrazole obtained according toExample 2 in 18 parts by weight of methanol

Furthermore, a solution of

(vi) 0.1 part by weight of azobisisobutyronitrile in 2 parts by weightof methanol and, one hour later, a solution of

(vii) 2 parts by weight of azobisisobutyronitrile in 40 parts by weightof methanol were added to the reaction mixture.

The resulting copolymer had a Fikentscher K value of 61.3 and an acidnumber of 61 mg of KOH/g of copolymer.

The copolymer prepared according to Examples 5, 6 and 7 were verysuitable for the production of photosensitive layers of offset printingplates.

We claim:
 1. A copolymer containing one or more copolymerized comonomersselected from the group consisting of4-[(meth)acrylamidomethyl]-pyrazoles and -isoxazoles of the formula (I)##STR8## where R, R¹, R², R³ and X independently of one another have thefollowing meanings: R is hydrogen or methyl, R¹ is hydrogen, methyl orethyl, R² and R³ may be identical or different and are each alkyl of 1to 6 carbon atoms or unsubstituted or methyl, t-butyl, or phenylsubstituted aryl of 6 to 20 carbon atoms and X is oxygen or an NR⁴group, where R⁴ is hydrogen or a radical having the meanings of R² orR³.
 2. A polymer consisting of one or more polymerized monomers selectedfrom the group consisting of 4-[(meth)acrylamidomethyl]-pyrazoles and-isoxazoles of the formula (I) ##STR9## where R, R¹, R², R³ and Xindependently of one another have the following meanings: R is hydrogenor methyl, R¹ is hydrogen, methyl or ethyl, R² and R³ may be identicalor different and are each alkyl of 1 to 6 carbon atoms or unsubstitutedor substituted aryl of 6 to 20 carbon atoms and X is oxygen or an NR⁴group, where R⁴ is hydrogen or a radical having the meanings of R² orR³.